Fig. 5. The product of local tissue curvature and ML tension can account for neck folding dynamics.

a Successive positions of the apical fold front, color-coded according to time (top), local tissue curvature (middle), and local deepening speed (velocity along the vector normal to the curve) of the apical fold front (bottom) for an individual pupa. Dashed line, midline position. See also Supplementary Movie 4. b Graph of the apical fold front deepening speed (mean ± sem) versus curvature (mean ± sem). Each point is the mean value (± sem) among 10 control animals for a given Position_ML at a given color-coded developmental time. For each developmental time, a line passing through the origin was fitted (R² values for each developmental time are indicated). c Schematic illustrating that the tissue line tension and the local tissue curvature define the magnitude of the normal resulting force (see text and Supplementary Note for details). d Graph of the apical fold front deepening speed (mean ± sem) and of the product of curvature and ML apical initial recoil velocity upon laser ablation in the neck region (mean ± sem) for a given Position_ML at a color-coded developmental time. Datasets from Fig. 1f and Fig. 2c were used (see corresponding figure legends for sample size). A line passing through the origin was fitted to the average values (R² = 0.96). e, f Graph of the apical fold front deepening speed (mean ± sem) versus the product of curvature and ML apical initial recoil velocity upon laser ablation in the neck region (mean ± sem) for a given Position_ML and selected genotypes: Dfd > Rok^RNAi, Dfd > Mbs^RNAi, Dfd > Tollo^RNAi, and Dg (e), or all tested experimental conditions (f). Datasets from Fig. 2e, Fig. 3a, Fig. 4a and Supplementary Fig. 8a were used (see corresponding figure legends for sample size). A line passing through the origin was fitted (black dashed line, R² values are indicated). Source data are provided as a Source Data file.